


For science?

by Carriefx



Category: Sherlock (TV)
Genre: (but not really and they both know it), First Kiss, First Time, For Science!, Friends to Lovers, M/M, Post Mary
Language: English
Status: Completed
Published: 2016-08-26
Updated: 2016-08-26
Packaged: 2018-08-11 03:36:46
Rating: Mature
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 5,560
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/7874671
Author URL: https://archiveofourown.org/users/Carriefx/pseuds/Carriefx
Summary: <blockquote class="userstuff">
              <p>An innocent conversation with Sherlock takes an unexpected turn, and before he knows it John has been persuaded that he should further explore his sexuality. A six-step “experiment” is in order. And Sherlock’s plans don't end there…</p>
            </blockquote>





	For science?

Sherlock’s experiments are often noisy, messy or otherwise unpleasant, but to be fair he generally has them under control. This evening proves an exception: a loud crack, followed by a yelp of pain, brings John running downstairs to the kitchen, where he finds his flatmate surveying the smoking ruins of his attempt to accelerate the ageing of stainless steel. The cheese grater has shattered, and several pieces of it are now embedded in Sherlock’s hand. “Stupid!” is Sherlock’s only comment, with an expression of profound self-disgust, and then, holding out his bleeding hand: “John, would you mind?”

A few minutes later, John has him sitting by the bathroom sink with swabs and towels, a large bottle of saline solution and a pair of tweezers, and has started the painstaking task of cleaning him up, testing for nerve damage and extracting the embedded metal. Sherlock appears to have retreated into his mind palace, responding mechanically to John’s requests and barely flinching as John probes his wounds. For a while they sit in companionable silence.

Then: “You are extraordinarily patient,” Sherlock remarks.

John smiles. “I’m your doctor. What choice do I have?”

“Yes, but this is beyond the call of duty,” Sherlock insists. “You’ve already spent nine hours at the clinic today, with no time to take a break. You’ve treated coughs and colds, hemorrhoids, angina, two vomiting babies and an obnoxious child with a red lollipop. You _had_ been looking forward to watching ‘ _Emmerdale_ ’ when you came home, although goodness knows why. Cleaning up after me instead is an act of friendship that I appreciate.”

John glances up, surprised. “No problem. I really should have sent you to A&E, though. If any of that metal went anywhere we can’t see it…”

“All the metal is present and accounted for. I can reconstruct the test sample to prove it. Besides,” Sherlock adds with deliberate emphasis, “I have complete faith in your abilities.”

“What’s got into you tonight?”

“Apart from half a cheese grater?”

“Yeah. What’s with the flattery? I’m not going to give up and send you to hospital, if that’s what you’re worried about.”

“Am I embarrassing you?”

“I’m not embarrassed. I’m just not used to you… you know. Being so appreciative.”

Sherlock huffs, but makes no reply. John carefully extracts a fragment of metal from his thumb pad and douses the cut with saline. “This one will need stitches too, I’m afraid.”

“You know best, John. As always.”

John looks up incredulously, but Sherlock appears to be perfectly serious. Disconcerted, John returns his attention to Sherlock’s hand, holding it steady as he positions the needle. He places the stitches quickly and neatly, but is increasingly aware of Sherlock’s gaze fixed on him as he works. The silence seems a little intense now, and he breaks it without thinking: “I’ll take these out in a week or so. Don’t try to do it yourself. And if you see any signs of infection in the meantime, you need to let me know. Redness, swelling…”

“I’ve had stitches before, John.” Sherlock reminds him.

“Yes. Well.” John ties off the thread. “You’re not always this cooperative.”

“Watching you work is surprisingly not boring.”

“Is that another compliment?”

“Not really. You can’t help being interesting.”

“I’m… interesting?” John asks, skeptically.

“Fascinating,” Sherlock confirms.

The room temperature seems to have risen several degrees. John feels distinctly hot under the collar. He suddenly becomes aware of how close together they are sitting: when he looks up, Sherlock’s face is only inches away. He looks quickly back down at Sherlock’s injured hand, which he is cradling in his, and the heat creeps into his cheeks.

“Now I _am_ embarrassing you,” Sherlock says, sounding inordinately pleased.

“I’m not embarrassed,” John says stubbornly. “For what it’s worth, I think you’re pretty interesting too. But you already know that. I mean…” He shakes his head, distractedly. “God, that sounds…”

“Flirtatious?” Sherlock suggests.

John frowns, startled. “I didn’t mean it like that.”

“Oh, no. Perish the thought.”

“I’m not…”

“Gay,” Sherlock finishes, flatly. “So you’ve said.”

There is something in his tone that unsettles John. In fact, Sherlock has deliberately steered the whole conversation into awkward territory. Not for the first time, John wishes he had the foggiest what the man is driving at. “I… don’t have a problem with people being gay, Sherlock,” he says, cautiously.

“I know you don’t,” Sherlock smirks. And then he drops his bombshell: “You even tried it yourself, once.”

There is a long, shocked pause. “Tried… being gay?” John says at last, his tone implying that he finds the idea highly improbable.

“Specifically: you attempted anal intercourse. With Major Sholto.”

John gapes at him. “No, I didn’t! We only…” He breaks off, narrowing his eyes. “Oh. You utter prick! You just said that so I’d contradict you.”

Sherlock’s smirk morphs into a real smile. “You only…?” he prompts.

John scowls and leans back against the sink. He’s trapped. There’s no way to evade Sherlock’s scrutiny until he’s finished treating his hand. And telling Sherlock that this is none of his business will be about as effective as shoring up a sandcastle against the incoming tide. He tries it anyway: “Look, I’d rather not talk about this, okay?”

“Why ever not? I’ve been told that it’s perfectly normal for close friends to discuss their sexual experiences, man-to-man.”

“Who the hell told you that?” John asks, but Sherlock merely gives him an enigmatic smile and raises his eyebrows expectantly. John groans. “Can’t you just… deduce it or something?”

“He was your commanding officer. You admired him very much…” Sherlock begins, his sing-song inflection indicating that he’s prompting John to continue the tale.

“Oh, all right.” John sighs. “Yes. He was… very good at his job. A good person, too. And…”

“Fit?” Sherlock supplies. “ _Rugged_?”

“Oh, for God’s sake, Sherlock! Shut up!”

“Sorry.” Sherlock makes a visible effort to repress a smile. “Go on.”

John takes a few deep breaths. Talking about Sholto with Sherlock is having an odd effect on him. It’s awkward as hell, but also somehow…liberating. Maybe Sherlock is right: maybe normal friends would have had this conversation years ago.

“I suppose you could say I had a crush on him,” he says, his eyes firmly fixed on the tweezers. “When I found out he was interested in me I was flattered. And I thought perhaps… But then when we tried, when it came down to it, it just felt wrong and I couldn’t really…I wasn’t… “. His bravado failing abruptly, he makes a vague downward gesture and leaves Sherlock to fill in the blanks. “So anyway, I learned my lesson. End of story.”

“You mean that on the basis of one unsuccessful homosexual encounter you concluded that any attraction you might feel towards another man must be illusory.” Sherlock says.

John winces, because, put like that, of course it sounds ridiculous. But his experience with Sholto _has_ influenced his subsequent behaviour towards other attractive men, notably Sherlock himself. Especially in the months leading up to his wedding, when Sherlock seemed more _available_ than ever before, John told himself repeatedly that he’d be an idiot to give up his physically and emotionally satisfying relationship with Mary for any uncertain something-beyond-friendship he imagined he might have with Sherlock. Mary was the wrong choice, obviously, but that doesn’t make him any less anxious about starting something he can’t follow through.

“I concluded that I’m not gay, Sherlock,” he says at last.

“You do know that ‘gay’ and ‘straight’ are just two ends of a spectrum?”

“Yes,” John says, shortly.

“Have you ever thought of conducting more tests to clarify your position on that spectrum?”

Oh, _wonderful_. John closes his eyes. “I’m quite happy as I am, thank you.”

“But you enjoy sex, are occasionally attracted to men and have no convincing reason to restrict yourself to one gender in your search for a partner.”

“Sherlock, please tell me you’re not suggesting I have sex with another man just to find out how straight I am.”

Sherlock leans forward. Outwardly he’s every inch the supportive friend, but there’s an undercurrent of excitement in his voice that does not bode well for John’s sanity. “If you find your test subject attractive, and if he’s informed and willing, why not?

“Because sexuality doesn’t work like that.”

“Then how does it ‘work’?”

“It… It’s…” John groans inwardly. He and Sherlock have _never_ talked about sex before. Why does the conversation have to go like this?! “It’s not logical. It’s not something you do to prove or disprove a hypothesis. Not at my age, anyway.”

“What’s age got to do with it?”

“You’re missing the point! I’m saying I don’t want to _use_ someone like that…”

“But if he’s informed and willing…”

“No!” John repeats, as repressively as he can. “Not good.”

Sherlock fixes him with the unblinking, analytical gaze he generally directs at tobacco ash. John does his best to meet that gaze defiantly, because this is absolutely _not_ something that Sherlock is going to talk him into. Not like all the other questionable things he has found himself doing in the name of ‘science’ over the years.

“You clearly have some ethical concerns,” Sherlock says slowly, “but the main issue here is that you’re not interested in the idea of sex with a hypothetical male partner, however attractive he might hypothetically be.”

John gives a mirthless laugh. “Got it in one.”

“So I suggest,” Sherlock continues, undeterred, “that to start with you have sex with a man you know and like. Preferably someone who’s interested in conducting his own experiment in parallel to yours, so there’s no question of anyone being _used_ , as you put it. For instance: someone who has previously been uninterested in sex but would consider attempting it with you.”

 _You mean…?_ John looks up, and time seems to stand still. Because Sherlock might have sounded casual, but he’s looking right back at John with a mixture of wariness and defiance, spots of color burning high in his cheeks. He appears to be holding his breath, waiting to see if John will pick up on his unsubtle hint. Because this is what Sherlock has been leading up to from the start. _You mean yourself_. They stare at each other for a long moment in silence.

“Right,” John says finally. He looks back down at their joined hands. “It’s not like I haven’t thought about that, once or twice,” he admits, his heart pounding against his ribs. “But – you probably already know this - there’s an emotional side to sex. When two people sleep together, things tend to change between them. And a lot of the time it turns out badly.”

“I’m aware of that John,” Sherlock replies, seriously. “But I do think that framing this encounter as an experiment will help to manage expectations. Both you and… your test subject are aware that there are three possible outcomes. If you both dislike the sex, nothing changes. If one of you enjoys it and the other does not, that’s unfortunate, but it’s a possibility that you’re both prepared for. No surprises, minimal embarrassment, no recriminations. And thirdly, you might both enjoy it. In that case…” Sherlock hesitates for a moment, “… in that case you might consider entering into a sexual relationship. And/or a romantic one.”

The words hang heavily in the air between them.

“I never thought you wanted…” John begins, but he can’t quite say it out loud. The concept of Sherlock, sexually attracted to him… Sherlock, in a relationship with him… is too improbable. He can’t shake the feeling that is all a colossal misunderstanding. “We’d have to start slowly,” he finds himself saying instead, the ‘we’ safely indeterminate. “Step by step, only going further if we’re both comfortable with what we’re doing.”

Sherlock nods. “I propose six steps, although when listed they do sound somewhat crude and pedestrian…”

“Go on, then,” John prompts, after a moment’s silence.

“The experiment will need to cover a range of activities,” Sherlock says, quickly and tonelessly. “I’ve attempted to sort them in ascending order of intimacy, although I’m aware that this is subject to debate. First: close physical proximity; second: kissing and caressing; third: hand jobs; fourth: frottage; fifth: blow jobs; sixth: anal intercourse.”

John gives a startled laugh, and Sherlock scowls at him. “As I said, they sound…”

“No, no, that’s fine. Sorry.” John clears his throat, licks his lips. “Fine. It’s just… ambitious, for one evening,” - and now he can’t carry on another second without making sure that the ‘hypothetical male partner’ is off the table - “...especially if my test subject has injured his hand.”

Sherlock’s lips twitch upwards. “It’s fortunate, then, that I’m practically ambidextrous.” And he raises his uninjured left hand and trails the tips his fingers gently down John’s cheek.

That touch makes everything real. Or rather, it turns John’s reality inside out. It’s like leaping off a cliff: for several long seconds his heart is lodged in his throat and his insides are in free fall. After so many years of admiring Sherlock, needing him, longing for him, loving him as a friend, he’s going to… well, _kiss_ him at the very least. “When?” he asks, inarticulately.

“No time like the present,” Sherlock says, withdrawing his hand and managing to sound almost businesslike. “The first step is close physical proximity, but obviously we’ve got that covered. Once you’ve finished stitching me up, we should try kissing and caressing.”

John nods dazedly, and picks up the tweezers again. Now, his hands are not so steady. He is achingly aware of every part of his body that’s touching Sherlock’s: his ankle, his knee, his hand… Unable to help himself, he runs his fingers up Sherlock’s wrist to his pulse point. Topping 100 beats per minute. Jumping at his touch…

“Concentrate, John.” Sherlock sounds amused but also… turned on? John has never heard that particular tone of voice from him before. He makes a valiant effort, focuses his wandering attention, and tends to the remaining cuts as thoroughly and gently as he’s able. After the longest ten minutes of his life, he positions the gauze and applies two bandages, wrapping them slowly around Sherlock’s fingers until most of his hand is encased.

“How does that feel?” he asks, pulling off his gloves.

“It’s comfortable. Thank you,” Sherlock says, his voice pitched low. And then, without further hesitation, they both lean in until their lips touch.

Their kiss is gentle at first, but charged with meaning. It doesn’t make John forget his wariness of physical attraction to another man, but the reality of Sherlock’s slight stubble and broad shoulders – the _strangeness_ of it, despite their years of intimacy - makes his heart beat faster. Then Sherlock cards his fingers through John’s hair, and John responds in kind by opening his mouth and slipping his tongue between Sherlock’s lips, smiling at his gasp of surprise. He runs his hands experimentally down Sherlock’s back, caressing him through his shirt as their tongues press together, and feels the familiar tug of lust in his stomach and groin, stronger and headier than he’s felt it in years. This is working… it’s more than working… and please God let Sherlock be feeling this too!

Trying not to rush, John places a hand on Sherlock’s knee as he once did so many months ago, but this time he slides it very slowly inwards and upwards. His other hand slips under Sherlock’s shirt onto the warm skin of his back. Sherlock shivers and breaks the kiss. “Shall we… go to my bedroom?”

“God, yes!” John exclaims with a thrill of triumph, and stands up quickly, pulling Sherlock with him.

Unfortunately, Sherlock’s bedroom turns out to be as untidy as John has ever seen it. A small bonfire’s worth of books and papers are strewn across the bed, and Sherlock darts forward with a muttered apology to clear some space, transferring his work into seemingly random piles on the floor. Aware from long experience that touching Sherlock’s clutter is counterproductive, John makes no offer to help, but simply watches him from the doorway, torn between exasperation and amusement. “I thought you’d planned this whole thing?”

“No! Well, obviously not _this_ ,” Sherlock brandishes his injured hand, distractedly. “I _had_ tried out our conversation in my head, but I didn’t expect to reach this point so soon. In reality you never say or do quite what I expect you to.”

“That’s just as well,” John says drily. He picks his way towards the bed. “You do have… er… “

“I was tested last month after that incident at the undertaker’s,” Sherlock says. He shovels the last of his papers unceremoniously onto the floor. “Clean. And you are too, so if you agree we can dispense with condoms until step six. I did buy some lubricant, though. Look.” He retrieves an assortment of bottles from his pocket and holds them out for John’s inspection.

John is reminded forcibly of their first day in 221b, when Sherlock was practically falling over his own feet to gain his approval. Strong as the attraction between them was, even then, John little imagined then that six years later he’d be standing with Sherlock beside his bed, about to make love to him. “You’ve never done this before, right?” he asks, finally voicing a question that has bothered him since their first evening together.

Sherlock lifts his chin. “Never. But I’ve done my research.” Then, still looking at John, he starts to unbutton his shirt.

He makes a surprisingly good job of it considering that he can use only one hand. John moves help him, but his eagerness – or Sherlock’s proximity – makes him clumsy at undoing the buttons bottom-up and backwards. Finally Sherlock bats his hands away – “Do your own!” – and they both start laughing.

Undressing with Sholto was solemn and erotic. With Sherlock, it feels natural. Almost. John drops his clothes onto the floor, grinning at the general chaos and at the sight of his friend struggling to pull down his slim-fit trousers. But by the time Sherlock steps out of his underwear, they are both serious again. John’s gaze drops instinctively to Sherlock’s crotch, then guiltily away, until he remembers a full second later that he’s allowed to look, now. His mouth goes dry, his stomach twisting into knots of excitement and apprehension.

Sherlock is watching him closely. “John, I think it might be easier for us both if I touch you first,” he suggests.

“Okay,” John agrees, hoarsely. “But can you just… can you kiss me again before we start?” And Sherlock obliges, kissing him keenly and deeply, keeping their lower bodies apart until John is half hard and pressing instinctively towards him.

Then they lie down, and Sherlock starts to touch John, one-handed, everywhere except for his groin. His touch is exploratory; he varies between the tips of his fingers and the palm of his hand, his tongue, lips and teeth, changing the pressure and the pace. It’s odd, and not entirely erotic, but rather intense. Unused to lying back passively, John rests his hand on Sherlock’s arm, feeling the muscles flex as Sherlock moves over him. He looks into his eyes - narrowed with concentration as Sherlock tests his reactions - and feels a slow, prickling arousal at being the focus of that fierce intelligence and attention.

“There’s a definite pattern here,” Sherlock murmurs, more to himself than to John, and then suddenly he becomes purposeful, narrowing his focus to a few sweet spots he’s identified. Now every touch is exactly as John needs it, attuned to his responses, sensual and unrelentingly precise. The effect is electric. As the pleasure escalates he can concentrate on nothing but Sherlock’s fingers and lips, and soon his whole body is straining towards Sherlock’s, so that a firm caress or an open-mouthed kiss which he enjoyed before now make him writhe and gasp. When Sherlock finally, _finally_ touches his cock there’s no room for awkwardness: John spreads his legs to give him access, and presses wantonly into his hand. He’s dimly aware that he’s moaning Sherlock’s name. His pre-come is slicking Sherlock’s fingers. Those lips against his throat… those fingers stroking him firmer and faster… _there!_ A warm wave of pleasure rocks his groin, and he comes hard. Sherlock shifts closer to him and strokes him through it, then runs his hand slowly back up to rest on John’s collar bone. They lie in silence for a while, both breathing heavily.

“That was incredible,” John says at last, struggling to find adequate words through the haze. “I mean… I should be embarrassed, really. I haven’t come that quickly since I was a teenager. But no one has ever… _read_ me like you just did.” He takes Sherlock’s hand and kisses it, tasting his own come on Sherlock’s fingers. A fierce, indefinable emotion is churning in his chest. “There’s no limit to what you can do.”

“It wasn’t just about what I did,” Sherlock says, quietly. “It was about you, and the way you responded to me. I’d never imagined it would be so intense.” He stares into the middle distance for a moment, biting his lip. “If you’re willing to reciprocate…”

“Oh yes, of course!” John exclaims, turning eagerly towards him. But then, despite himself, he hesitates, because really, what could be good enough for Sherlock after _that_? All his experience gleaned from short-term relationships with women seems irrelevant when faced with this man who’s become the undisputed centre of his universe. The second possible outcome of their experiment is suddenly foremost in his mind. He desires Sherlock – can’t believe he ever doubted that – but what if Sherlock doesn’t, or can’t, desire him?

“Oh, for God’s sake, John!” Sherlock huffs, grabbing John’s hand and placing in unceremoniously on his half-hard cock. “You’ll never know unless you try.”

John gives a startled laugh, and tries to shake off his uncharacteristic uncertainty. This is only Sherlock, after all, and whatever pedestal you place him on, he refuses to stay there for more than a minute. “I’m getting there,” he promises. “Just give me a moment.”

He uses that moment to really look at his friend. Confident as he’d seemed, Sherlock clearly isn’t entirely comfortable with the situation. He’s let go of John and crossed his arms defensively over his stomach. His forehead is furrowed, his eyes shut, and he’s practically vibrating with nervous tension. John thinks about easing that tension away, or redirecting it…

Keeping his hand where it is, he shifts his fingers so that he’s cradling Sherlock’s testicles, massaging him gently. Without stopping, he moves closer, tangling his legs with Sherlock’s, half leaning over him and bringing their mouths together. Sherlock gives a shaky sigh and relaxes into the kiss, even as his cock slowly hardens under John’s palm. So far, so good.

John shifts his kisses to Sherlock’s jaw and then his neck, losing himself in the warm, familiar scent of him, and the salty skin beneath his lips. When he touches the tip of his tongue to Sherlock’s pulse point, Sherlock’s breathing becomes ragged, and John pushes him gently onto his back, letting go of his cock for a moment in favour of running both hands up his chest and pressing kisses to his throat. John’s fingers reach Sherlock’s taut nipples and he squeezes gently; Sherlock groans and thrusts up against him… and then suddenly Sherlock is scrambling into a sitting position, overbalancing as he tries to put weight on his injured hand, his eyes wide with shock.

“Shit!” John exclaims before he can help himself. “Sorry! Did I hurt you?”

“No!” Sherlock pants, seeming to recover himself. “No, that was good. Don’t stop.” He lies down again and grabs John’s hand, but John resists.

“There must have been something wrong or you wouldn’t have reacted like that.”

“I was just surprised.” Sherlock says, sounding furious with himself. “But I’m fine now. Really.”

John looks down at him, trying to calm his own racing thoughts. He feels shocked himself, and guilty and slightly hurt. But then he remembers Sherlock’s involuntary groan and the twitch of his body, and has a glimmer of understanding. “When I touched you, it made you react in a way you didn’t expect – is that it?”

“For a moment I couldn’t think.” Sherlock says, wincing. “I lost control of my mind and my body. Sorry. It won’t happen again.”

John lies back down so that they’re face to face. “You saw how out of control I was when you touched me,” he says slowly. “There’s not really a right or a wrong way to respond to… you know. Sex. But if you try to think your way through it, you might not enjoy it so much.”

This is clearly neither a new nor a welcome idea to Sherlock. “Don’t think, just feel,” he parodies, with a grimace. “That seems to be fairly common advice on websites for the sexually uninitiated. But I didn’t realise losing control was a _necessary_ part of the experience.”

John bites his lip. “Maybe it’s not necessary, but it is kind of the best bit...” Unable to resist, he traces his fingers gently down Sherlock’s side. “Look, this is an experiment, right? And it’s just you and me. If I do something that feels good, you could try just letting go and seeing where it takes you. And if you don’t want to, that’s fine too. I’ll stop whenever you tell me to.”

For about a minute Sherlock appears undecided. John forces himself to stay quiet and give him space. But then: “I suppose we could try that,” Sherlock mutters at last. “As an experiment.” He turns his gaze to the ceiling, the frown of determination settling back over his face. John can practically hear the command “let go!” resonating through his mind like a mantra.

He considers him for a moment, then smiles. “Pass me the lube.”

Surprised, Sherlock reaches over and passes him the bottles from the bedside table. John warms the lube in his hands then spreads it generously over both of them. His cock is already tingling again, just at the thought of what he’s about to do.

Sherlock is watching him, wide-eyed. “Frottage is…” he begins.

“Yeah, I’ve moved onto step whatever-it-is.” John confirms. “Is that okay?” Then, leaving Sherlock plenty of time to refuse, he leans forward until their cocks touch. They both gasp.

“Oh. Yes!” Sherlock exclaims, more loudly than he probably intended. “Okay. Good.”

In response, John presses in harder, and Sherlock clutches his waist convulsively. Then, hooking a leg behind Sherlock’s calf, John carefully aligns them and starts to rock his hips. The movement is familiar, but everything else is new and exquisite: the slide of Sherlock’s erection against his, the thick scent of his arousal, the strength and the pliancy of his body. It’s one of the most intimate things John has ever experienced. Having come already, he feels no urgency, unlike Sherlock, who is soon pushing erratically up against him. “Focus on me.” John murmurs. “Stay with me.” And Sherlock starts to match his rhythm, engulfing them both in a giddy rush of sensation. John longs to whisper encouragement, but isn’t sure whether that would help or distract him. He settles for nuzzling his throat and jaw, until Sherlock twists his head and meets his lips in a breathless, open-mouthed kiss.

Sherlock’s injured arm is flung out beside him, but his good hand is still gripping John’s waist with painful force. Acting on instinct, John prizes it off and stretches Sherlock’s arm above his head, pinning him down and intertwining their fingers. Sherlock’s face goes slack, and his whole body arches out of rhythm. “John, _oh_ … Yes…”

John speeds up a little, keeping as much contact between them as he can and willing Sherlock not to panic. He’s slick with sweat now as well as lube, but the angle is perfect. Sherlock’s breath stutters, and a moment later John feels the force of his orgasm everywhere they touch. He’s hardly even aware of his own physical pleasure: it's subsumed by his overwhelming desire to draw the moment out forever, and to feel every inch of Sherlock’s trembling body against his. Even once Sherlock relaxes completely, sinking into the mattress with an exhausted sigh, John can’t bring himself to let him go. But he pulls back slightly to look at him: Sherlock’s pale face is flushed and his hair is in disarray, his lips swollen and parted. His eyes focus on John with an expression of awe and confusion, and a vulnerability that makes John’s chest ache.

It’s easy for John to read Sherlock’s emotions because they mirror his own. For a moment he feels completely out of his depth. The coward in him longs to deflect this with a joke – his usual joke about people who might talk. He resists, because he owes Sherlock more than that. But the alternative is frankly terrifying. He never talks about his feelings, and neither does Sherlock, which is presumably why he seduced him this way. The “experiment” gave them both the chance to set aside the weight of expectations and lower the emotional stakes. Maybe that’s still the best approach, even now.

“I think our experiment was worthwhile,” John remarks, sounding as warm and relaxed as he can. “Don’t you agree?”

Sherlock hesitates, then rolls his eyes, some of his usual arrogance returning to his face. “John, it should be blatantly obvious, even to you, that our ‘experiment’ didn’t dignify the name of scientific enquiry. There were no pre-agreed objective criteria for success or failure. Only two participants, both self-selected and with a strong personal interest in the outcome. And as you say, sexuality is hopelessly illogical anyway.”

Technically, that doesn’t answer the question, but John is light-headed with relief all the same. He knows that expression and that tone of voice well enough to sense that everything will be fine between them. “It’s not like you to bollocks up an experiment,” he teases. “Did you collect some useful data at least?”

“I really can’t comment at this early stage,” Sherlock matches his tone, giving a lazy smirk. “We haven’t yet completed all the activities on the list. I take it you’d be willing to try some more at a later date?”

“Absolutely,” John says, without hesitation.

“With the same self-selected participant?”

“Screw scientific rigour,” John agrees, giddy and ecstatic and completely unable to stop smiling. “Only with you. And…um… that includes the part about the relationship, if that’s what you want.”

“A sexual relationship?”

“And/or a romantic one.”

Sherlock blinks several times. “Would you marry me?” he asks, suddenly.

“ _Marry_ you?!” John’s smile vanishes. He fixes his eyes on Sherlock’s face, looking for any sign that he’s teasing or joking, but it’s impossible to tell. “God, Sherlock!” he says weakly. “That’s a bit sudden. Are you actually proposing to me, or is it just hypothetical?”

Sherlock frowns. “Given your response, I’d say it’s hypothetical.”

“No, wait!” John exclaims. “Let’s get this straight. Um… unintended irony, there.” He takes a few deep breaths. “We’ve only been sleeping together for what, half an hour?”

“You think it’s too soon.”

“Not necessarily,” John says, then repeats it with more conviction. “Actually, no. But I need to know that you’re really serious. I mean, a minute ago we were joking about it all being an experiment, and I know it’s more than that, but marriage is a whole different ball game.” He swallows hard. “I _would_ marry you.”

Sherlock’s eyes widen. “John, of course I’m serious! I’ve wanted to marry you since the day I saw you proposing to someone else - though I realise that’s not good and I probably shouldn’t say it. I know sex is important to you, so I had to see if that side of things could work between us, hence this whole “experiment” - which, incidentally, has been something of a paradigm shift. But this isn’t about sex for me, and it certainly isn’t about idle curiosity. You said… _romantic relationship_ … so I thought…”

Sweaty, sticky and exhausted as he is, John kisses Sherlock so hard that neither of them can breathe.

“Wait!” Sherlock gasps at last. “I hadn’t finished…”

“I love you,” John says, completely unable to help himself. “I love you so much, Sherlock. I’d do anything to be with you.”

“That’s what I was going to say!” Sherlock sounds almost indignant, although his smile tells a different story. “You know I can’t say it back to you now. Rhetorically it would have no impact whatsoever.”

“Rhetorically. Right.” John fights the urge to giggle. “Sorry to steal your thunder.”

“I’ll have to paraphrase,” Sherlock says. “John, I want to be as close to you as I can get. Physically. Legally. _Emotionally_.” He underlines his words by shifting forwards until their foreheads are touching, and slinging his arm around John’s waist, pulling him closer still. “I don’t even believe in marriage, in general, but with you it’s the next logical step.”

“Number… eight on the list?” John asks, closing his eyes and tangling his fingers in Sherlock’s hair. “Right after the anal sex and the romantic relationship?”

“Concurrently with, I hope,” Sherlock corrects him. “And I think the list might need expanding.”

“For science, of course.”

“And _sentiment_ ,” Sherlock murmurs against his lips.

**Author's Note:**

> Thank you so much for reading! :-)


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